What colors can I use that would give color to my grayish/bluish couch? HELP!?

I think out of all of those colors, I'd choose brown and blue accents. Dark brown goes with black, white, and red easily, and it can bring out the blue in a greyish/blue couch. Dark brown and blue is a great combo.

Try to alternate between dark brown and blue throw pillows. Find something with a pattern so they color pops when you look at it. Add mirrors here and there to reflect the color. Throw pillows should be in a similar color/pattern. You can find so much out there right now in brown or blue.

On your windows, add sheer curtains. They will allow light in and if you follow the color theme they will bring a uniformity to your room.

On your rug, add a big area rug with your colors in it. An area rug like this Blue and Beige contemporary would draw your eye away from the couch and onto the floor, livening up the room.

Other items I'd add to your room: patterned picture frames or word art (ie: friends, family, love, etc.) Lamps add light and ambiance, and if you have a chocolate lamp shade it adds color to your room.

If you find that you still aren't happy with the couch, you can cover it up with a slip cover. They are fairly inexpensive now, and you can find them at Ikea, Ross, TJ Maxx, and other stores.